Siloxane-based resin and a semiconductor interlayer insulating film using the same

ABSTRACT

A siloxane-based resin having a novel structure and a semiconductor interlayer insulating film using the same. The siloxane-based resins have a low dielectric constant in addition to excellent mechanical properties and are useful materials in an insulating film between interconnect layers of a semiconductor device.

BACKGROUND OF THE INVENTION

This non-provisional application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 2003-44119 filed on Jul. 1,2003, the subject matter of which is herein incorporated by reference.

1. Field of the Invention

The present invention generally relates to siloxane-based resins andsemiconductor interlayer insulating films using the same. Morespecifically, the present invention is directed to siloxane-based resinshaving a new structure, which is used to prepare a semiconductorinterlayer insulating film.

2. Description of the Related Art

As the circuit density of multilevel integrated circuit devicesincreases, the performances of devices come to depend on a line rate.So, it needs reducing the capacitances of interlayer insulating films ofthe devices revealed methods to decrease the resistance and capacity ofthe line. Specifically, U.S. Pat. Nos. 3,615,272; 4,399,266; 4,756,977and 4,999,397 disclose the formation of insulating films by the SOD(spin on deposition) method using polysilsesquioxanes having adielectric constant of 2.5–3.1 as well as good planarization properties.

The hydrosilsesquioxanes as well as preparation methods thereof are wellknown in the art. For example, U.S. Pat. No. 3,615,272 discloses amethod of preparing a completely condensed, solublehydrogensilsesquioxane resin, which comprises the steps of condensingtrichlorosilanes in a sulfuric acid medium and washing the resultingresin with water or aqueous sulfuric acid. Also, U.S. Pat. No. 5,010,159discloses a method of synthesizing a soluble condensed hydridosiliconresin, which includes the steps of hydrolyzing hydridosilanes in anarylsulfuric acid hydrate-containing a hydrolysis medium and contactingthe resulting resin with a neutralizing agent. U.S. Pat. No. 6,232,424describes a highly soluble silicon resin composition having excellentsolution stability, which was prepared by hydrolyzing and polycondensingtetraalkoxysilane, organosilane and organotrialkoxysilane monomers inthe presence of water and a catalyst. U.S. Pat. No. 6,000,339 describesthat a silica-based compound is useful for improving the resistance tooxygen plasma and physical properties as well as thickness of a coatingfilm, which can be obtained through reacting a monomer selected from thegroup consisting of alkoxysilane, fluorine-containing alkoxysilane andalkylalkoxysilane with a titanium- or zirconium-alkoxide compound in thepresence of water and a catalyst. U.S. Pat. No. 5,853,808 describes thatsiloxane and silsesquioxane polymers, useful for forming SiO₂-richceramic coatings, can be obtained from hydrolysis and polycondensationof organosilanes having a β-substituted alkyl group. EP 0 997 497 A1discloses that hydrolyzation and polycondensation of a certaincombination of alkoxysilanes including mono-, di-, tri-,tetraalkoxysilane and trialkoxysilane dimers can provide resinousmaterials for insulating films.

SUMMARY OF THE INVENTION

The present invention features the production of a siloxane-based resinhaving excellent mechanical properties as well as very low dielectricconstant, and the formation of a low dielectric insulating film usingthe siloxane-based resin.

One aspect of the present invention relates to a siloxane-based resinthat is prepared by hydrolyzing and condensing a silane-based monomerhaving a radial structure of Formula 1 and at least one monomer selectedfrom the group consisting of the compounds of Formulas 2 to 4, inorganic solvent in the presence of an acid or alkaline catalyst andwater:Si[(CH₂)_(k)SiY₁Y₂Y₃]4  Formula 1

-   -   wherein,    -   k is an integer of 1–10; and    -   Y₁, Y₂ and Y₃ are independently a C₁–C₃ alkyl group, a C₁–C₁₀        alkoxy group, or a halogen atom, provided that at least one of        them is hydrolysable,

-   -   wherein,    -   R₁ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group;    -   X₁, X₂ and X₃ are independently a hydrogen atom, a C₁–C₃ alkyl        group, a C₁–C₁₀ alkoxy group, or a halogen atom, provided that        at least one of them is hydrolyzable;    -   m is an integer of 0–10; and    -   p is an integer of 3–8,

-   -   wherein,    -   R₂ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group;    -   X₄ is a hydrogen atom, or a C₁–C₁₀ alkoxy group;    -   Y₁ is a hydrogen atom, a C₁–C₃ alkyl group or a C₁–C₁₀ alkoxy        group; and    -   n is an integer of 0–10, and        R₃SiX₅X₆X₇  Formula 4    -   wherein,    -   R₃ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group;    -   X₅, X₆ and X₇ are independently a hydrogen atom, a C₁–C₃ alkyl        group, a C₁–C₁₀ alkoxy group, or a halogen atom, provided that        at least one of them is hydrolyzable.

Another aspect of the present invention relates to a method of forming asemiconductor interlayer insulating film, comprising the step of:providing a resin solution by dissolving the siloxane-based resin in anorganic solvent; coating a silicon wafer with the resin solution; andheat-curing the resulting coating film.

Still another aspect of the present invention relates to an interlayerinsulating film made using the above siloxane-based resin.

The present invention provides a siloxane-based resin with superiorsolubility through the condensation of a radial silane-based monomer ofFormula 1 and at least one compound selected from the group consistingof compounds of Formulas 2 to 4.

The siloxane-based resin has a dielectric constant of 3.0 or less sothat it is suitable for application as a low dielectric coating film.

Also, the present invention provides the method of preparing aninsulating film by coating a silicon wafer with a solution containingthe above siloxane-based resin in an organic solvent and heat-curing theresulting coating film.

According to the present invention, the combined use of a porogen withthe inventive siloxane-based resin may further lower the dielectricconstant of the final insulating film down to 2.50 or less. The presentinvention is represented by:Si[(CH₂)_(k)SiY₁Y₂Y₃]4  Formula 1

-   -   wherein,    -   k is an integer of 1–10; and    -   Y₁, Y₂ and Y₃ are independently a C₁–C₃ alkyl group, a C₁–C₁₀        alkoxy group, or a halogen atom, provided that at least one of        them is hydrolyzable.

-   -   wherein,    -   R₁ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group;    -   X₁, X₂ and X₃ are independently a hydrogen atom, a C₁–C₃ alkyl        group, a C₁–C₁₀ alkoxy group, or a halogen atom, provided that        at least one of them is hydrolyzable;    -   m is an integer of 0–10; and    -   p is an integer of 3–8.

-   -   wherein,    -   R₂ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group;    -   X₄ is a hydrogen atom, or a C₁–C₁₀ alkoxy group;    -   Y₁ is a hydrogen atom, a C₁–C₃ alkyl group or a C₁–C₁₀ alkoxy        group; and    -   n is an integer of 0–10, and        R₃SiX₅X₆X₇  Formula 4    -   wherein,    -   R₃ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group;    -   X₅, X₆ and X₇ are independently a hydrogen atom, a C₁–C₃ alkyl        group, a C₁–C₁₀ alkoxy group, or a halogen atom, provided that        at least one of them is hydrolyzable.

In the preparation of the above siloxane-based resin, the monomer ofFormula 1 and the monomer selected from the group consisting of thecompounds represented by Formulas 2 to 4 are mixed in a molar ratio of1:99 to 99:1.

Preferable acid or base catalysts for the preparation of the inventivesiloxane-based resin can be exemplified by, but are not limited to,hydrochloric acid, nitric acid, benzene sulfonic acid, oxalic acid,formic acid, potassium hydroxide, sodium hydroxide, triethylamine,sodium bicarbonate and pyridine. Such a catalyst is used so that molarratio of the catalyst to the monomers is 0.000001:1–10:1.

The amount of water used in the preparation of the inventivesiloxane-based resin is 1–1000 mol per 1 mol of the monomers, so thatmolar ratio of water to the monomers is 1:1–1000:1.

Non-limiting examples of the organic solvent used in the preparation ofthe inventive siloxane-based resin include aliphatic hydrocarbonsolvents such as hexane; aromatic hydrocarbon solvents such as anisole,mesitylene and xylene; ketone-based solvents such as methyl isobutylketone, 1-methyl-2-pyrrolidinone, cyclohexanone and acetone; ether-basedsolvents such as tetrahydrofuran and isopropyl ether; acetate-basedsolvents such as ethyl acetate, butyl acetate and propylene glycolmethyl ether acetate; alcohol-based solvents such as isopropyl alcoholand butyl alcohol; amide-based solvents such as dimethylacetamide anddimethylformamide; silicon-based solvents; and mixtures thereof.

According to the present invention, the hydrolysis and polycondensationreaction is carried out at a temperature of 0–200° C., preferably50–110° C., for 0.1–100 hrs, preferably 5–48 hrs.

The siloxane-based resin thus prepared has a Mw of 3,000–300,000. TheSi—OR content in the entire terminal groups preferably amounts to morethan 5 mol %.

The present invention also provides a method of forming an interlayerinsulating film for a semiconductor device using the inventivesiloxane-based resin. The insulating film has a low dielectric propertybelow 3.0 and shows excellent mechanical and heat resistance properties.According to the present invention, such an insulating film can beobtained by coating a silicon wafer with a solution containing theinventive siloxane-based resin in an organic solvent and heat-curing theresulting coating film. That is, the inventive siloxane-based resindissolved in an organic solvent is applied onto a substrate. Then, theorganic solvent is evaporated through simple air-drying or by subjectingthe substrate, at the beginning or following the heat-curing step, to avacuum condition or to mild heating at a temperature of 200° C. or less,so that a resinous coating film can be deposited on the surface of thesubstrate. Thereafter, the resinous coating film is cured by heating thesubstrate at a temperature of 150–600° C., preferably 200–450° C., for1–150 minutes, so as to provide an insoluble, crack-free film. As usedherein, by “crack-free film” is meant a film without any cracks that canbe observed with an optical microscope at a magnification of 1000×. Asused herein, by “insoluble film” is meant a film that is substantiallyinsoluble in any solvent described as being useful for dissolving theinventive siloxane-based resin.

According to the present invention, the combined use of a porogen withthe inventive siloxane-based resin may further lower the dielectricconstant of the final insulating film down to 2.50 or less. As usedherein, by “porogen” is meant any pore-generating compounds. In case ofusing a porogen, an additional step is required of heating the resinousfilm over the decomposition temperature of the porogen so that theporogen can be decomposed.

The porogen used in the present invention may be any of thepore-generating compounds well know in the art, which can be exemplifiedby, but are not limited to, cyclodextrin, polycaprolactone, andderivatives thereof. The porogen is mixed in content of 1–70 wt %, basedon a solid content of the siloxane-based resin.

Preferred organic solvents for the dissolution of the siloxane-basedresin or the porogen to provide a liquid coating composition can beexemplified by, but are not limited to, aliphatic hydrocarbon solventssuch as hexane; aromatic hydrocarbon solvents such as anisole,mesitylene and xylene; ketone-based solvents such as methyl isobutylketone, 1-methyl-2-pyrrolidinone, cyclohexanone and acetone; ether-basedsolvents such as tetrahydrofuran and isopropyl ether; acetate-basedsolvents such as ethyl acetate, butyl acetate and propylene glycolmethyl ether acetate; alcohol-based solvents such as isopropyl alcoholand butyl alcohol; amide-based solvents such as dimethylacetamide anddimethylformamide; silicon-based solvents; and mixtures thereof.

In the preparation of the liquid coating composition, the weight ratioof solid component containing the siloxane-based resin and the porogenis preferably 5–70 wt % based on the total composition. The organicsolvent should be used in an amount sufficient to apply the solidcomponents including the siloxane-based resin and the porogen evenly tothe surface of a wafer. Thus, the organic solvent should amount to20–99.9 wt %, preferably 70–95 wt % of the liquid coating composition.If the organic solvent content of the liquid coating composition is lessthan 20 wt %, part of the siloxane-based resin remains undissolved. Onthe other hand, if the organic solvent content is more than 99.9 wt %,the final resinous film is as thin as 1000 Å or less.

In the present invention, the liquid coating composition thus preparedcan be applied to a silicon wafer according to various coating methodswell known in the art. Non-limiting examples of the coating methoduseful in the present invention include spin-coating, dip-coating,spray-coating, flow-coating and screen-printing, while spin-coating ismost preferred.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be described in more detail withreference to the following Examples. However, these examples are givenfor the purpose of illustration only and should not be construed aslimiting the scope of the present invention.

EXAMPLE 1 Synthesis of Monomer EXAMPLE 1-1 Synthesis of Monomer (A)

Monomer (A)

Si[CH₂CH₂SiCH₃(OCH₃)]₄

73.384 mmol (10.0 g) of tetravinylsilane and 0.2 g of platinum(O)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (solution inxylene) are introduced into a flask, and then diluted with 300 ml oftetrahydrofuran. Next, the flask is cooled to −78° C., and 322.888 mmol(37.145 g) of dichloromethylsilane is slowly added thereto, after whichthe reaction temperature is gradually elevated to room temperature. Thereaction is continued at room temperature for 40 hours, and thenvolatile materials are removed from the reaction mixture under a reducedpressure of about 0.1 torr. To the reaction mixture is added with 100 mlof hexane and stirred for 1 hour, followed by filtering through celiteto afford a colorless, clear solution. And then, hexane is removed fromthe resulting solution under a reduced pressure of 0.1 torr, to afford aliquid compound represented by the following Formula:Si[CH₂CH₂SiCH₃Cl₂]₄

16.778 mmol (10.0 g) of the above liquid compound is diluted with 500 mlof tetrahydrofuran, to which 150.999 mmol (15.28 g) of triethylamine isadded. Then, the reaction temperature is cooled to −78° C., and 150.999mmol (4.83 g) of methylalcohol is slowly added to the reaction solution,after which the reaction temperature is gradually elevated to roomtemperature. The reaction is continued at room temperature for 15 hrs,followed by filtering through celite, and then volatile materials areevaporated from the filtrate under reduced pressure of about 0.1 torr.

To the resulting solution is added 100 ml of hexane, and stirred for 1hour, followed by filtering through the celite. Filtrate obtained fromthe filtration of the stirred solution is subjected to a reducedpressure to remove hexane therefrom and afford monomer (A) as acolorless liquid. The results obtained from NMR analysis of this monomerdissolved in CDCl₃, are as follows:

¹H NMR(300 MHz) data; δ 0.09 (s, 12H, 4×-CH₃), 0.48–0.54 (m, 16H,4×—CH₂CH₂—), 3.53 (s, 48H, 4×—[OCH₃]₈)

EXAMPLE 1–2 Synthesis of Monomer (B)

29.014 mmol (10.0 g) of2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane and 0.164 g ofplatinum (O)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (solutionin xylene) are introduced into a flask, and then diluted with 300 ml ofdiethyl ether. Next, the flask is cooled to −78° C., and 127.66 mmol(17.29 g) of trichlorosilane is slowly added thereto, after which thereaction temperature is gradually elevated to room temperature. At roomtemperature, the reaction is continued for 40 hours, and then thevolatile material is removed from the reaction mixture under a reducedpressure of 0.1 torr. To the resulting solution is added 100 ml ofhexane, and stirred for 1 hour, and filtered through celite. Filtrateobtained from the filtration of the stirred solution is subjected to areduced pressure to remove hexane therefrom under a reduced pressure of0.1 torr, to afford a liquid compound represented by the followingFormula:

11.28 mmol (10.0 g) of the above liquid compound is diluted with 500 mlof tetrahydrofuran, to which 136.71 mmol (13.83 g) of triethylamine isadded. Then, the reaction temperature is cooled to −78° C., and 136.71mmol (4.38 g) of methylalcohol is slowly added to the reaction solution,after which the reaction temperature is gradually elevated to roomtemperature. The reaction is continued at room temperature for 15 hours,and the reaction solution is filtered through celite. The volatilematerial is removed from the reaction mixture under a reduced pressureof 0.1 torr. To the remaining filtrate is added 100 ml of hexane andstirred for 1 hr, followed by filtering through celite. To the obtainedfiltrate is further added 5 g of activated carbon, and stirred for 10hours, followed by filtering through celite. From the filterate is thenremoved hexane under a reduced pressure to afford a colorless liquidmonomer (B). The results obtained from NMR analysis of this monomerdissolved in CDCl₃ are as follows:

¹H NMR(300 MHz) data; δ 0.09 (s, 12H, 4×—CH₃), 0.52–0.64 (m, 16H,4×—CH₂CH₂—), 3.58 (s, 36H, 4×—[OCH₃]₃)

EXAMPLE 1–3 Synthesis of Siloxane-based Monomer (C)

249.208 mmol (10.0 g) of 1,3-dichlorotetramethyldisiloxane is introducedinto a flask, and then diluted with 500 ml of tetrahydrofuran. Next, theflask is cooled to −78° C., and 108.212 mmol (10.95 g) of triethylamineis added thereto. And then, 107.990 mmol (3.46 g) of methyl alcohol areslowly added to the flask, after which the reaction temperature isgradually elevated to room temperature. The reaction is continued atroom temperature for 15 hours, and the reaction solution is filteredthrough celite. The volatile material is removed from the filtrate undera reduced pressure of 0.1 torr. To the remaining filtrate is added 100ml of hexane, and stirred for 1 hour, followed by filtering throughcelite. And then, from the filtrate the hexane is removed under areduced pressure to produce a colorless liquid. Colorless liquid monomer(C) is obtained from simple distillation of the liquid. The resultsobtained from NMR analysis of this monomer dissolved in CDCl₃ are asfollows:

¹H NMR(300 MHz) data; δ 0.068(s, 12H, 4×—CH₃), 3.45(s, 6H, 2×—OCH3)

EXAMPLE 1–4 Synthesis of Siloxane-based Monomer (D)

A monomer (D) is synthesized in the same manner as in Example 1–2, withthe exception that 1,5-dichlorohexamethyltrisiloxane is used, instead of1,3-dichlorotetramethyldisiloxane.

The results obtained from NMR analysis of the monomer (D) thus preparedand dissolved in CDCl₃ are as follows:

¹H NMR(300 MHz) data; δ 0.068 (s, 12H, 4×—CH₃), 0.077 (s, 3H, —CH₃),3.44 (s, 6H, 2×—OCH₃)

EXAMPLE 1–5 Synthesis of Siloxane-based Monomer (E)

A monomer (E) is synthesized in the same manner as in Example 1–2, withthe exception that 1,7-dichlorooctamethyltetrasiloxane is used, insteadof 1,3-dichlorotetramethyldisiloxane.

The results obtained from NMR analysis of the monomer (E) thus preparedand dissolved in CDCl₃ are as follows:

¹H NMR(300 MHz) data; δ 0.068(s, 24H, 8×—CH3), 3.45(s, 6H, 2×—OCH₃)

EXAMPLE 1–6 Siloxane-based Monomer (F)

The monomer (F), purchased from Sigma. Aldrich Co., USA, is used.

EXAMPLE 1–7 Siloxane-based Monomer (G)

Monomer (G)CH₃Si(OCH₃)₃

The monomer (G), purchased from Sigma. Aldrich Co., USA, is used.

EXAMPLE 2 Synthesis of Siloxane Resin

The siloxane-based monomer (A) having a radial structure connected withorganic groups, and at least one monomer of the monomers (B) through (G)are placed into a flask, and diluted with tetrahydrofuran 15 times asmuch as the total amounts of the monomers in the flask. Then, the flaskis cooled to −78° C. At −78° C., predetermined amounts of hydrochloricacid (HCl) and water are added to the flask, after which the reactiontemperature is gradually elevated to 70° C. The reaction is continued at70° C. for 20 hours. At the completion of the reaction, the reactionmixture is transferred to a separatory funnel, followed by addition ofdiethylether and tetrahydrofuran as much as the tetrahydrofuran used inthe previous dilution of the monomer. Then, 3×washing is conducted, eachround with water one tenth as much as the total solution in theseparatory funnel. After washing, volatile materials are evaporated fromthe remaining solution to produce white powdery polymers. The powder iscompletely dissolved in a small amount of acetone to obtain a clearsolution, and this solution is filtered through a 0.2 μm syringe filterso as to remove impurities to provide a clear filtrate, to which is thenslowly added deionized water. As a result, white powdery material isformed, which is then separated from the liquid phase (mixed solution ofacetone and water) and dried for 10 hrs at a temperature of 0–20° C.under a reduced pressure of about 0.1 Torr to produce a fractionatedsiloxane-based resin.

TABLE 1 Siloxane Monomer (mmol) HCl H₂O Final Resin Resin (A) (B) (C)(D) (E) (F) (G) (mmol) (mmol) (g) (a) 8.402 3.599 0.110 368 3.45 (b)4.798 4.799 0.096 320 2.87 (c) 2.569 5.999 0.098 308 2.95 (d) 10.7034.587 0.095 316 3.52 (e) 10.703 4.587 0.095 316 3.46 (f) 10.703 4.5870.095 316 3.35 (g) 10.703 4.587 0.104 578 3.97 (h) 12.487  5.351 0.116386 3.62 (i) 12.487 12.487 0.138 457 3.56 (j) 10.703 24.973 0.160 5343.41 (k) 8.919 80.271 0.312 1040  7.52

EXAMPLE 3 Composition Analysis

The respective siloxane-based resins obtained from the above Example 2are analyzed for Si—OH, Si—OCH₃, S₁—CH₃ content, as described below. Theresults are set forth in Table 2.

TABLE 2 Siloxane Resin Si—OH (%) Si—OCH₃ (%) Si—CH₃ (%) (a) 33.9 2.164.0 (b) 39.2 1.3 59.5 (c) 35.7 0.8 63.5 (d) 24.9 1.5 73.6 (e) 27.1 1.071.9 (f) 27.5 1.0 71.5 (g) 25.9 0.9 73.2 (h) 27.7 6.6 65.7 (i) 21.5 5.173.4 (j) 24.9 4.5 70.6 (k) 24.3 2.7 73.0 Note: Si—OH content, Si—OCH₃content, and Si—CH₃ content were analyzed by use of a nuclear magneticresonance analyzer(Bruker Co.), and calculated from the followingequations: Si—OH (%) = Area(Si—OH) ÷ [Area(Si—OH) + Area(Si—OCH₃)/3 +Area(Si—CH₃)/3] × 100, Si—OCH₃ (%) = Area(Si—OCH₃)/3 ÷ [Area(Si—OH) +Area(Si—OCH₃)/3 + Area(Si—CH₃)/3] × 100, Si—CH₃ (%) = Area(Si—CH₃)/3 ÷[Area(Si—OH) + Area(Si—OCH₃)/3 + Area(Si—CH₃)/3] × 100.

EXAMPLE 4 Measurement of Thickness and Refractive Index of Thin Film

The siloxane-based resins obtained from the above Example 2, and theirmixture with heptakis(2,3,6-tri-O-methoxy)-β-cyclodextrin are dissolvedin propylene glycol methyl ether acetate (PGMEA), respectively, so thatfinal concentration of the solid matter in the resulting liquid coatingcompositions is 25 wt %. Each of the coating compositions is thenspin-coated onto a silicon wafer for 30 seconds while maintaining thespin rate of 3,000 rpm. In a nitrogen atmosphere, the coated wafers aresubjected to the sequential soft baking on a hot plate (1 min at 100° C.and another minute at 250° C.) so as to sufficiently evaporate theorganic solvent. Thereafter, the temperature is elevated to 420° C. at arate of 3° C./min under vacuum condition, at which temperature thecoating films are allowed to cure for 1 hr to produce test pieces.

Each of the test pieces thus prepared is analyzed for film thickness andrefractive index. The film thickness and the refractive index aremeasured at 5 different points every test piece by the use of a profilerand a prism coupler, respectively. The mean thickness and refractiveindex are set forth in Table 3 along with their uniformity.

TABLE 3 Composition of resinous film Siloxane Siloxane Resin PorogenThick. Refractive Uniformity Uniformity of Resin (wt %) (wt %) (Å)Index(R.I.) of R.I. (%) Thick. (%) (a) 100 — 10230 1.4460 0.054 1.07 (a)70 30 9879 1.3374 0.071 0.98 (b) 100 — 10255 1.4494 0.049 0.85 (b) 70 3010030 1.3369 0.031 0.86 (c) 100 — 9876 1.4393 0.035 0.87 (c) 70 30 95801.3375 0.087 0.76 (d) 100 — 11030 1.4275 0.081 0.53 (d) 70 30 100901.3417 0.096 0.54 (e) 100 — 10200 1.4245 0.063 0.36 (e) 70 30 100101.3417 0.108 0.38 (f) 100 — 10650 1.4324 0.087 0.56 (f) 70 30 100301.3655 0.105 0.46 (g) 100 — 11200 1.4240 0.054 0.51 (g) 70 30 110001.3490 0.087 0.51 (h) 100 — 11050 1.4211 0.034 1.38 (h) 70 30 100601.3366 0.069 1.54 (i) 100 — 9980 1.4174 0.087 1.52 (i) 70 30 9750 1.33710.116 1.48 (j) 100 — 11020 1.4145 0.041 1.20 (j) 70 30 10200 1.33170.068 0.97 (k) 100 — 10135 1.4077 0.079 1.02 (k) 70 30 9980 1.3371 0.0940.97

EXAMPLE 5 Measurement of Dielectric Constant

P-type silicon wafers doped with boron are coated with a 3000 Åthermally-oxidized silicon film, followed by sequential deposition of a100 Å of titanium layer, a 2000 Å of aluminum layer and a 100 Å oftitanium layer using a metal evaporator. On the surface of each of thesewafers is formed a resinous film in the same manner as in the aboveExample 4. Subsequently, on the resinous film is deposited a circularelectrode of 1 m diameter which consists of a 100 Å-thick titanium layerand a 5000 Å-thick aluminum layer through a hard mask so as to provide atest piece having a MIM (metal-insulator-metal) structure. Test piecesthus prepared are subjected to measurement of capacitance at 100 kHzusing PRECISION LCR METER (HP4284A) with Micromanipulator 6200 probestation. Dielectric constant of each test film is calculated from thefollowing equation, wherein “d” value was obtained by the use of anellipsometer:k=C×d/∈ ₀ ×A

-   -   wherein,    -   k: dielectric constant    -   C: capacitance    -   ∈₀: dielectric constant in vacuum    -   d: the thickness of low dielectric film    -   A: the contact area of electrode

The calculated dielectric constants are set forth in Table 4.

TABLE 4 Thin Film Composition Dielectric Siloxane Resin Siloxane Resin(wt %) Porogen (wt %) Constant (a) 100 — 2.79 (a) 70 30 2.26 (b) 100 —2.78 (b) 70 30 2.28 (c) 100 — 2.74 (c) 70 30 2.31 (d) 100 — 2.70 (d) 7030 2.30 (e) 100 — 2.71 (e) 70 30 2.31 (f) 100 — 2.75 (f) 70 30 2.27 (g)100 — 2.76 (g) 70 30 2.28 (h) 100 — 2.70 (h) 70 30 2.25 (i) 100 — 2.76(i) 70 30 2.27 (j) 100 — 2.72 (j) 70 30 2.28 (k) 100 — 2.76 (k) 70 302.30

EXAMPLE 6 Measurement of Hardness and Modulus

Test pieces prepared as in the above Example 4 are analyzed for hardnessand elastic modulus using Nanoindenter II(MTS Co.). The resinous film ofeach test piece is indented until the indentation depth reached 10% ofits whole thickness. At this time, to secure the reliability of thismeasurement, 6 points are indented every test piece, and mean hardnessand modulus are taken. The results are set forth in Table 5.

TABLE 5 Thin Film Composition Siloxane Siloxane Porogen Hardness ModulusResin Resin (wt %) (wt %) (GPa) (GPa) (a) 100 — 1.05 5.47 (a) 70 30 0.613.15 (b) 100 — 0.97 4.78 (b) 70 30 0.54 2.72 (c) 100 — 0.87 4.33 (c) 7030 0.41 2.64 (d) 100 — 0.87 3.74 (d) 70 30 0.44 2.37 (e) 100 — 0.90 3.27(e) 70 30 0.48 2.40 (f) 100 — 0.87 3.84 (f) 70 30 0.42 2.51 (g) 100 —0.94 3.97 (g) 70 30 0.47 2.60 (h) 100 — 0.76 4.01 (h) 70 30 0.32 2.82(i) 100 — 0.78 3.87 (i) 70 30 0.34 2.71 (j) 100 — 0.75 3.81 (j) 70 300.32 2.55 (k) 100 — 0.76 3.89 (k) 70 30 0.34 2.51

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. A siloxane-based resin prepared by hydrolyzing and condensing asilane-based monomer having the structure of Formula 1, and at least onemonomer selected from the group consisting of compounds of Formulas 2 to4, in an organic solvent in the presence of an acid or alkaline catalystand water:Si[(CH₂)_(k)SiY₁Y₂Y₃]₄  Formula 1 wherein, k is an integer of 1–10; andY₁, Y₂ and Y₃ are independently a C₁–C₃ alkyl group, a C₁–C₁₀ alkoxygroup, or a halogen atom, provided that at least one of them ishydrolyzable,

wherein, R₁ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group; X₁, X₂ andX₃ are independently a hydrogen atom, a C₁–C₃ alkyl group, a C₁–C₁₀alkoxy group, or a halogen atom, provided that at least one of them ishydrolyzable; m is an integer of 0–10; and p is an integer of 3–8,

wherein, R₂ is a C₁–C₃ alkyl group, or a C₆–C₁₅ aryl group; X₄ is ahydrogen atom, or a C₁–C₁₀ alkoxy group; Y₁ is a hydrogen atom, a C₁–C₃alkyl group or a C₁–C₁₀ alkoxy group; and n is an integer of 0–10, andR₃SiX₅X₆X₇  Formula 4 wherein, R₃ is a C₁–C₃ alkyl group, or a C₆–C₁₅aryl group; X₅, X₆ and X₇ are independently a hydrogen atom, a C₁–C₃alkyl group, a C₁–C₁₀ alkoxy group, or a halogen atom, provided that atleast one of them is hydrolyzable.
 2. The siloxane-based resin accordingto claim 1, wherein the molar ratio of the monomer of Formula 1 to themonomer selected from the group consisting of compounds of Formulas 2 to4 is 1:99 to 99:1.
 3. The siloxane-based resin according to claim 1,wherein the catalyst is selected from the group consisting ofhydrochloric acid, nitric acid, benzene sulfonic acid, oxalic acid,formic acid, potassium hydroxide, sodium hydroxide, triethylamine,sodium bicarbonate, pyridine, and mixtures thereof.
 4. Thesiloxane-based resin according to claim 1, wherein the molar ratio ofthe monomer to the catalyst is 1:0.000001 to 1:10.
 5. The siloxane-basedresin according to claim 1, wherein the molar ratio of the monomer towater is 1:1 to 1:1000.
 6. The siloxane-based resin according to claim1, wherein the hydrolysis and condensation reactions are performed at0–200° C. for 0.1–100 hours.
 7. The siloxane-based resin according toclaim 1, wherein the organic solvent is selected from the groupconsisting of an aliphatic hydrocarbon solvent, an aromatic hydrocarbonsolvent, a ketone-based solvent, an ether-based solvent, anacetate-based solvent, an alcohol-based solvent, an amide-based solvent,a silicon-based solvent, and mixtures thereof.
 8. The siloxane-basedresin according to claim 1, wherein the weight average molecular weightof the resin is 3,000 to 300,000.
 9. A semiconductor interlayerinsulating film, comprising the siloxane-based resin of claim
 1. 10. Thesemiconductor interlayer insulating film according to claim 9, whereinmicropores are formed throughout the film by the use of a porogen. 11.The semiconductor interlayer insulating film according to claim 10,wherein the porogen is selected from the group consisting ofcyclodextrin, polycaprolactone and derivatives thereof.